Moments later, at 3:20 a.m., the magnitude 6.0 quake struck six miles southwest of the little winemaking community of Napa, according to Caltech.

The quake injured 120 people there, including three critically, and left 7,000 people without power. In the aftermath, inoperative hydrants damaged by the shaking made it difficult for firefighters to combat several blazes sparked by the quake. The temblor also damaged dozens of buildings and caused close to $1 billion in property damage, according to the Los Angeles Times.

“I kept waiting for it to stop,” said former Pasadena resident Ronda Carson, who lives in Walnut Creek, about an hour’s drive from Napa, a city of about 78,000 residents. Walnut Creek, population about 64,000, didn’t sustain any measurable damage, but other communities near Napa did, such as Vallejo. There, 312 structures sustained light to severe damage, with 16 water main breaks. Vallejo City Manager Dan Keen declared a state of emergency in that community of 117,000.

“I got in survival mode real quick, just in that small amount of time. I started looking for what I needed if I had to leave my place,” Carson recalled. “After it stopped, I couldn’t go back to sleep. I was sitting there waiting for the aftershock. A lot of people didn’t sleep for hours because they were waiting for aftershocks.”

According to emergency officials, the area could have experienced massive casualties if the quake had struck later in the day, when more people would have been on the streets and in high-rise buildings.

Julia Cornejo, 34, said she woke up to her bed swaying beneath her. “It felt like a huge rocking bassinet,” Cornejo said.

“After it was over, I was anticipating the aftershocks, but there weren’t any. I was scared to go back to sleep though. The mood up here right now, well, I can say it is frightening, especially for people who live in the Bay Area. With huge buildings and by the water, it just equals chaos.”

So far, there have been an estimated 65 aftershocks since the earthquake, with two of those registering at least magnitude 3.0. Two hours after the original earthquake, a magnitude 3.7 shaker rattled the area.

In 1989, the Loma Prieto quake, measuring magnitude 6.9, struck the Santa Cruz area during the World Series, also known as the Battle of the Bay between the San Francisco Giants and the Oakland As. The quake, which hit during Game 3, with Oakland visiting Candlestick Park, killed 62 people, injured 3,757 and caused $6 billion in damage. Prior to that, the area had experienced quakes of magnitudes 5.7 and 5.8 in 1983 and 1980, respectively.

In Peru, a magnitude 6.9 quake hit at 4:21 p.m., but because it occurred in a rural and sparsely populated area, there were no reports of damage or injuries, according to The Associated Press.

In Mexico Sunday, a 16-foot long, 8-foot wide fissure appeared in the farmland of Sonora, leaving many to speculate that an earthquake had occurred along the San Andreas Fault. Seismologist claimed that there had been no activity along the fault in that area, while scientists at the University of Sonora speculated the ground depression was caused by an underground water channel.

Since the 1970s, seismologists have predicted that California will be struck by a monster quake of a magnitude 7 or larger at some point. An early warning system could help prevent thousands of deaths in such an event.

“Today’s successful use of the early earthquake warning system shows that a full West Coast system would be successful in giving residents, businesses and critical infrastructure an important warning of a large magnitude earthquake,” Rep. Adam Schiff (D- Burbank) said in a prepared statement. ”While this was not the ‘big one,’ we need to be prepared to save lives and protect vital infrastructure — even a few seconds of warning will allow people to seek cover, automatically slow or stop trains, pause surgeries and more.”

The House Appropriations Committee, of which Schiff is a member, requested $5 million to fund the Earthquake Early Warning System earlier this year. So far, Congress has not acted on that legislation. It will cost about $40 million to build the system on the West Coast and $16 million a year to maintain it, according to the US Geological Survey (USGS).

The system, which was designed by scientists from Caltech, USGS, the University of California and the University of Washington, would be used to not only warn local residents of a pending earthquake, but could also be used to stop elevators and shut off gas lines and other utilities near the epicenter of an earthquake. The warning system would also send alerts to cell phones and emails.

Similar systems are already in place in Mexico and Japan. Japan’s system has given residents there up to a two-minute warning of an impending quake. According to the USGS, those systems were not put into place until after devastating quakes caused hundreds of deaths.

According to the USGS, 42 states have a “reasonable” chance of experiencing damaging ground shaking from an earthquake, and 16 of those states have a relatively high likelihood of sustaining damage.

“We think there are a lot of things that can be gained as far as reducing the loss of life from an automated warning system, as warning the general public to reduce losses during an earthquake,” said seismologist Elizabeth Cochran.

A warning system could also provide valuable time to first responders, said Pasadena Emergency Management Coordinator Lisa Derderian.

“It’s not a lot of time,” said Derderian, who is also spokesperson for the Pasadena Fire Department. “But it is enough time to stop people from getting into an elevator, to stop surgeries and procedures at hospitals. If we get 10 seconds that is enough to get our apparatus doors open, and get some equipment out. Our doors are not supposed to jam in an earthquake, but they haven’t really been tested in a large earthquake. Our worst fear is not being able to get our equipment out in a large earthquake.”

Derderian said that a great deal of public education and outreach would be required if the warning system were ever implemented.

Michele Trinidad, 36, who lives in Daly City and attends the University of San Francisco, said the quake was traumatic, but it has woken people up.

“It felt more like rocking and swaying,” Trinidad said. “There were no aftershocks in my area but more towards the epicenter. People are still shaken up but are now more aware of earthquake preparedness.”